Transforming Growth Factor-Beta Induces Senescence in Hepatocellular Carcinoma Cells and Inhibits Tumor Growth
Transforming Growth Factor-Beta Induces Senescence in Hepatocellular Carcinoma Cells and Inhibits Tumor Growth
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DOI：
10.1002/hep.23769
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发表时间：
2010-09-01
期刊：
影响因子：
13.5
通讯作者：
Ozturk, Mehmet
中科院分区：
文献类型：
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作者：
Senturk, Serif;Mumcuoglu, Mine;Ozturk, Mehmet
诱导衰老是治疗肝细胞癌的一种有效方法。然而，在这些癌症中，主要的衰老诱导物(p53和p16(Ink4a))经常被灭活。我们测试了转化生长因子-β(转化生长因子-β)是否可以作为肝细胞癌的潜在衰老诱导剂。首先，我们筛选了具有完整的转化生长因子-β信号的肝细胞癌细胞系，这些细胞株导致小母亲抵抗十足瘫痪(Smad)靶向基因的激活。5株细胞满足此条件，且对转化生长因子-β1(1-5 ng/mL)处理均表现出较强的衰老反应。治疗后c-myc表达下调，p21(Cip1)和p15(Ink4b)表达上调，细胞停滞于G(1)期。P16(Ink4a)未被诱导表达，衰老反应与P53状态无关。不到1分钟的短时间暴露就足以产生强劲的衰老反应。P21(Cip1)和p15(Ink4b)的强制表达概括了转化生长因子-β1的作用。衰老反应与烟酰胺腺嘌呤二核苷酸磷酸氧化酶4(NOX4)诱导减少和细胞内活性氧(ROS)积累有关。用ROS清除剂N-乙酰-L-半胱氨酸处理细胞，或沉默NOX4基因，可以挽救p21(Cip1)和p15(Ink4b)的积聚，以及对转化生长因子-β的生长停滞。在免疫缺陷小鼠体内生长的人肝癌肿瘤也表现出转化生长因子-β1诱导的衰老。更重要的是，每隔4天在肿瘤周围注射转化生长因子-β1(2 Ng)可使肿瘤生长减少75%以上。相反，TGF-β受体2的缺失在体外取消了衰老反应，并极大地加速了体内肿瘤的生长。结论：在高分化的肝癌细胞中，转化生长因子-β诱导的衰老停滞不依赖于p53和p16(Ink4a)，而依赖于NOX4，依赖于p21(Cip1)，依赖于p15(Ink4b)，依赖于ROS。此外，转化生长因子-β在体内诱导的衰老与强烈的抗肝癌反应有关。(《肝病》2010；52：966-974)
Senescence induction could be used as an effective treatment for hepatocellular carcinoma (HCC). However, major senescence inducers (p53 and p16(Ink4a)) are frequently inactivated in these cancers. We tested whether transforming growth factor-beta (TGF-beta) could serve as a potential senescence inducer in HCC. First, we screened for HCC cell lines with intact TGF-beta signaling that leads to small mothers against decapentaplegic (Smad)-targeted gene activation. Five cell lines met this condition, and all of them displayed a strong senescence response to TGF-beta 1 (1-5 ng/mL) treatment. Upon treatment, c-myc was down-regulated, p21(Cip1) and p15(Ink4b) were up-regulated, and cells were arrested at G(1). The expression of p16(Ink4a) was not induced, and the senescence response was independent of p53 status. A short exposure of less than 1 minute was sufficient for a robust senescence response. Forced expression of p21(Cip1) and p15(Ink4b) recapitulated TGF-beta 1 effects. Senescence response was associated with reduced nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) induction and intracellular reactive oxygen species (ROS) accumulation. The treatment of cells with the ROS scavenger N-acetyl-L-cysteine, or silencing of the NOX4 gene, rescued p21(Cip1) and p15(Ink4b) accumulation as well as the growth arrest in response to TGF-beta. Human HCC tumors raised in immunodeficient mice also displayed TGF-beta 1 induced senescence. More importantly, peritumoral injection of TGF-beta 1 (2 ng) at 4-day intervals reduced tumor growth by more than 75%. In contrast, the deletion of TGF-beta receptor 2 abolished in vitro senescence response and greatly accelerated in vivo tumor growth. Conclusion: TGF-beta induces p53-independent and p16(Ink4a)-independent, but Nox4-dependent, p21(Cip1)-dependent, p15(Ink4b)-dependent, and ROS-dependent senescence arrest in well-differentiated HCC cells. Moreover, TGF-beta induced senescence in vivo is associated with a strong antitumor response against HCC. (HEPATOLOGY 2010;52:966-974)